New Front Diff

The Range Rover’s front vibration is getting a little worse.  It happens at about 50-60mph with light throttle loads, but now also seems to be appearing at 70-ish mph on slightly rough roads.

The problem has existed since I bought the vehicle, and replacements of prop shaft UJs, tyres, CV joints, wheel bearings, brake discs and swivel pins have made no difference.  The oil weep from the diff pinion lead me to find a small amount of radial play in the pinion bearings, so the diff had been awaiting a rebuild for some time.

The probelm is, as always, the matter of minimising the time the car is off the road without spending a fortune.  I have never rebuilt a diff, and while it looks simple in principle, it also looks fiddly and time consuming.  A recon diff from Aschrofts was going to cost a little over £300 after VAT, and a Genuine Parts recon unit from LR about £360 (which is what I’d have gone for of the two), but with so many other pressing jobs and priorites, I can’t justify that expense on a suspect but unconfirmed source of only minor trouble.

So, I have bought a good second hand unit from a Discovery 300Tdi axle from Rogers of Bedford.  I had to remove the diff myself, though they did offer to do it for me at a later point, but by removing it myself I was better able to assess its condition (including assessing the condition of the rest of the axle and its oil) and can rest assured it wasn’t dropped or contaminated with dirt.  They let me put it through the parts washer a few times to clean it up and it appears to be absolutely mint – very little back lash, no apparent wear or chipping on the teeth at all and unmarked splines and cross pins.  Coming from a Discovery, it’s likely to have had a gentler life than from a Defender and had less strain with the open centre diff than a RRC’s unit with the wind-up caused by the viscous coupling in the Borg Warner transfer box (I’m told the wear in mine is likely to be from that, and that RRC’s often suffer front diff wear around the cross-pin and its locating holes in the carrier from those forces, which sounds highly plausible considering how stiff the viscous couplings are).  I paid £100, which is more than they go for in private sales on the various forums, but it’s a low mileage unit that is unblemished, unlike so much of what else is about.  So, I just need the time and the weather to fit it…